High aluminum, silicon levels found in Fujairah bunker fuel: FOBAS

Marine fuel oil testing services company Fuel Oil Bunkering Analysis and Advisory Service has found a high level of aluminum and silicon (Al+Si/catfines) from bunker fuel samples taken at Fujairah last week, the company said in a client note Wednesday.

The aluminum and silicon levels ranged from marginally above 75 mg/kg up to nearly double at 139 mg/kg, above the 95% confidence limit of ISO827:2017 RMG/RME and RMK grades.

High level of aluminum and silicon is abrasive and may damage fuel pumps, fuel injectors and cylinder components.

Al+Si at 75mg/kg can be difficult to reduce, and "may be manageable," but Al+Si at levels of up to 139 mg/kg "would prove extremely difficult to bring down to acceptable levels for engine entry," said FOBAS.

One way to reduce the high levels of aluminum and silicon in the fuel is to let the fuel remain in settling tanks for the maximum possible time, then heat the fuel at an appropriate temperature to separate the aluminum and silicon through settling, the note said.

A steady-state fuel through-put temperature of 98 degrees Celsius will enhance "separator efficiency," and the "de-sludge cycle frequency may be increased to optimize bowl cleanliness and separation efficiency in removing aluminum and silicon from the fuel oil," it said.

Both settling and service tanks should be drained off at regular intervals, FOBAS advised.

If the bunker fuel is tested Al+Si off-spec, FOBAS recommends that further samples from the upper, middle, lower and bottom of the respective bunker tankers be taken to confirm the original result, so as to establish the distribution of the catfines in the tanks.

"As good general practice, we would recommend regular checks of purifier performance by having samples taken from the inlet and outlet of all purifiers analyzed for at least water, ash and element concentration, including Al+Si, to be confident of purifier performance at all times," said FOBAS.

It added that it is "extremely important" to take bunker drip samples during bunkering process so that the quality of the bunkered fuel can be ascertained.